The accumulator batteries that supply driving power to an electric vehicle occupy in their aggregate a considerable part of the total vehicular weight and bulk, thereby restricting transport capacity of the vehicle which would be otherwise left available. Battery capacity sets the driving range and in recharging run-down batteries, it becomes obligatory that the vehicle be rendered immobile for several hours on the average. Rapid recharge systems would reduce this binding time to the order of several ten minutes but only in exchange for a ceiling held at no more than 60 percent of the full battery capacity, extremely high voltage and current to force through, attendant hazards and shortened battery-life. Battery swapping systems, another attempt to reduce the binding time, have not yet been satisfactorily developed. As a result the operator of an electric vehicle is invariably held under a psychological strain of fear for being unexpectedly stranded.
An object of the present invention then is to provide an electricity supply unit for electric vehicles which does not occupy the interior of an electric vehicle but permits added transport capacity to the vehicle while providing a supplemental source of electricity.
It is another object of this invention to provide an electricity supply unit for electric vehicles which is itself transportable, and hence easily attached to or detached from a vehicle while its battery pack can be easily replaced.
It is a further object of this invention to provide an electricity supply unit for electric vehicles which generates additional electricity while attached to a running vehicle.